Refrigerator-wall of wood pulp



No Model.)

0. D WOOLWORTH. REFRIGERATOR WALL 0P WOOD PULP.

Patented June 10, 1890.

With

m m t m S W003 Pul naw/whoa 5 m 1% MW UNITED STATES PATENT OFFICE.

CHARLES D. \VOOLWVORTH, OF CHICAGO, ILLINOIS, ASSIGNOR TO CALVIN O.WOOLIVORTI-I, OF CASTLETON, NEW YORK.

REFRIGERATOR-WALL OF WOOD PULP.

SPECIFICATION forming part of Letters Patent No. 429,830, dated June 10,1890.

Application filed June 24, 1889. Serial No. 315 385- (No model.)

To all whom it may concern.-

Be it'known that I, CHARLES D. WooL- WORTH, a citizen of the UnitedStates, and a resident of Chicago, in the State of Illi nois, haveinvented a new and useful Improvement in Refrigeratoralls of Wood Pulp,of which the following is a specification.

It has long been known that wood pulp as compacted and molded incentrifugal machines is in its virgin or natural state an excellentnon-conductor of heat, and various attempts have been made to utilize itfor the walls of refrigerators and water-coolers. One method heretoforeemployed was to indurate the pulp cylinders the same as other pulp ware;but it was found that this very materially reduced the non-conductingquality of the Wood pulp, and to this extent lessened its utility. InPatent No. 374,183, to Charles 13. Gardner, it is proposed to confinethe chemical treatment of the cylinders to about one-third of thethickness toward the center at each surface, leaving the central ormiddle portionabout one-thirdin its natural or virgin state. I haveinvented an improvement in such refrigerator wall, whereby practicallythe entire thickness of the Wood pulp may be preserved in its virgin ornatural state, and at the same time protected against absorbingmoisture, and adapted to be decorated in the usual or suitable ways.

Another object of this improvement is to prevent imparting to thecontents of the refrigerators any odors, as those of the resin andnaphtha and linseed-oil commonly used in the chemical treatment of thepulp preliminary to ordinary induration.

A sheet of drawings accompanies this specification as part thereof.

Figurel of the drawings represents a crosssection of a hollow pulpcylinder as it comes from the centrifugal moldiugmachine. Fig. 2represents a like view of the same at an intermediate stage of itstreatment; and Fig. 3 represents a like view of the finished cylinderready for use as the walls of a cylindrical refrigerator.

In carrying this invention into effect I first produce, in customarymanner, by means of a centrifugal pulp-molding machine, a hollowcylinder of wood pulp, Fig. 1, having suitable thickness and otherproportions for the walls of a given size of cylindrical re- Ufrigerator or a given zone thereof. The same is then thoroughly dried ina suitable manner. This is best done in a kiln heated to a temperatureof from 130 Fahrenheit up. The outside surface is then sandpapered toremove its mold-marks and adapt it to receive the required finish. Acoating of gluesuch as is known as sweet glue, the same being perfectlysweet and free from smell-is then applied to all parts of the cylinder,and the latter is again baked until the glue is thoroughly dry. Aperfectly-hard superficial coating is thus formed both on the inside andon the outside of the cylinder, as illustrated by Fig. 2, leaving theentire thickness of the pulp in its original state with itsnon-conducting qualities un impaired. The outside may be supercoated inany approved way to waterproof and finish it. Japan paint followed by acoat of varnish is preferred. To the inside a coating of shellac isapplied, which renders this surface hard and water-proof and at the sametime free from all smell. The finished cylin der is represented by Fig.3.

The refrigerator may be completed according to any approved plan.

Any required cutting of the cylinder should be done after its surfacesare hardened by the coatings of glue baked dry, as aforesaid. Thisinsures smooth edges, which are preferably hardened by two coats ofshellac, as the latter dries quickly, and but a small quantity isrequired for this purpose; but the cut edges may alternatively be coatedwith the glue and the cylinder again baked.

Having thus described the said improvement, I claim as my invention anddesire to patent under this specification A hollow cylinder of wood pulphaving its in its natural or original state and the insurfaces providedwith a coating of sweet terior is rendered odorless, substantially as oglue and with a superposed coating" of shelhereinbefore specified, forthe purpose set lac 011 the inner surface of the cylinder, forth.

5 and any approved waterproofing and fin- CHARLES D. \VOOLVVORTH.

ishing-coatings superposed on the outer Vitnesses: surface of thecylinder, whereby the entire .T. E. CAILEY,

thickness of the pulp cylinder is preserved GEO. B. PARKER.

